1096P - Camrelizumab plus apatinib in patients with advanced mucosal melanoma: A 3-year survival update with biomarker analysis

Background

Mucosal melanoma (MM) is an aggressive melanoma subtype with poor response to programmed death receptor 1 (PD-1) inhibitors monotherapy. Our previous single-arm, phase 2 trial (ChiCTR1900023277) reported that camrelizumab plus apatinib had promising antitumor activity in advanced mucosal MM. Here, we reported the 3-year follow-up results from this trial.

Methods

Patients with inoperable stage III-IV or recurrent/metastatic MM received camrelizumab (200 mg biweekly) and apatinib (500 mg daily) until disease progression or intolerable toxicity. In this report, we updated the secondary endpoints of progression-free survival (PFS) and overall survival (OS) with an extended follow-up of 3 years. Peripheral blood samples, collected at baseline and after 2 cycles of treatment, were analyzed for lymphocyte phenotypic profiling and cytokine levels to assess their prognostic value.

Results

Thirty-two patients were enrolled between April 2019 and June 2022. At the cut-off date of 15 April 2024, the median follow-up was 36.21 months (IQR: 3.75-39.59). The median PFS was 8.05 months (95% CI, 6.77-11.89), and the median OS was 14.26 months (95% CI, 11.56-24.54). The OS rates at 1, 2, and 3years were 64.29%, 30.25%, and 20.74%, respectively. Notably, after 2 cycles of treatment, we observed a significant decrease in the proportion of PD-1 positive T lymphocytes (CD3+CD8+CD279+ cells). In addition, the change from baseline in the proportion of NK cells (CD3-CD16+CD56+ cells) was significantly higher in patients who responded to treatment (complete or partial response) than in those who did not respond (stable disease or disease progression). Higher IFN-γ levels at baseline correlated with improved OS (HR = 0.28) and a trend toward better PFS. Patients with lower IFN-γ at baseline had a median OS of 10.81 months, whereas those with higher levels did not reach the median OS.

Conclusions

The 3-year survival update demonstrated that camrelizumab plus apatinib provided long-term survival benefits in advanced MM patients. Peripheral blood levels of PD-1-positive T lymphocytes, NK cells and IFN-γ hold promise as prognostic biomarkers.

Clinical trial identification

ChiCTR1900023277.

Editorial acknowledgement

Legal entity responsible for the study

Z. Zou.

Funding

This work was supported by the National Natural Science Foundation of China (No. 82073365, No. 81872484), the Social Development Fund of Jiangsu Province (No.BE2019605).

Disclosure

All authors have declared no conflicts of interest.